FIELD OF INVENTION

The present invention relates generally to electric starter motor used for motor vehicles and more specifically to a compact size low current (low power), low speed and high torque electric starter motor intended for two wheeled and three wheeled vehicles.

BACKGROUND OF THE INVENTION

Existing automobile technology discloses starter motors of different sizes based upon the input power, revolution counts or output torque. Usage of reduction gear mechanism for getting higher torque is disclosed in automobile industry but only for high power input motors.

Typically such motors will have power output of 250W-500W, current rating in order of 20A to 40A, producing torque 0.8Nm to 2.2Nm. Such motors are assembled onto the vehicles thru' reduction gear means to produce overall reduction of 20 to 25.

Since the current rating is very high, body grounding is required using high current carrying wires for safety reasons. Further, use of such motors for starting purposes requires higher capacity battery and relays.

Hence there is a need to overcome the above problem associated with starter motor of high current (high current).

SUMMARY OF THE INVENTION

Objective of the present invention is to provide an electric starter motor characterized by its no grounding requirement, compact size and ability to produce high torque in the range 0.8 Nm - 2.2 Nm, having a main housing member. This housing member is defining a front housing member, a centre housing member and a rear housing member.

An armature assembly is extending through the centre housing member and defining a front armature member having a pinion shaft and a rear armature member.

Said rear armature member has a commutator such that a rotatable armature shaft is engaged with the front armature member through engagement of said pinion shaft and a reduction gear of 2.8: 4.5 ratios,
housed in the front housing member.

Said electric starter motor further has a brush card of dielectric material, holding multiple electrical conducting brushes, secured in the rear housing member such that brushes are engaged with the commutator. BRIEF DESCRIPTION OF DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are incorporated in and constitute embodiments of the invention, illustrate several aspects of the invention and together with a description of the embodiments serve to explain the principles of the invention and thus, are not limited of the present invention and a brief description of the drawings is as follows:

Figure 1 is the cross-sectional view of the claimed starter motor describing the essential embodiments of the invention.

Figure 2 is a schematic diagram showing an essential feature for enablement of the claimed invention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described for enablement purpose. The invention may have application to all two and three wheeled vehicles.

Figure 1 is the cross-sectional view of claimed starter motor showing essential embodiments of the invention.

Said starter motor has a main housing 100 divided into three parts i.e. front housing 101, centre housing, 102 and rear housing 103. Said front housing 101 and rear housing 10.3 are made up of resin material so that compact size of the motor can be maintained and grounding requirement of the motor can be waived or removed.

An armature assembly 104 is secured in the centre housing 102 such that front part 105 defined by the pinion shaft 107 of the motor, is secured near the front housing 101 and the rear part 106 of the armature defined by the commutator 108 of the motor is secured near the rear housing 103.

Centre housing 102 of the motor has a magnet wall 113 secured on inner periphery of the centre housing 102 so that flux can be generated around the armature 104 to operate starter motor.

Further rear housing 103 has a brush card 109 made up of dielectric material used to hold electrical conducting brushes 110 engaged with the commutator 108 (current range of 5 Amp to 15 Amp) so that current is transferred to armature 104 and produce mechanical power of 60W to 150W.
Pinion shaft 107 of the motor is engaged to the rotatable armature shaft 111 through a reduction gear 112 ( 2.8 to 4.5 ratio) secured in the front housing 101 and transferring required torque of 08 Nm to 2.2 Nm to the engine starting means.

As shown in Figure 2, first input terminal 203 of starter motor 202 is connected to the power source i.e. battery 201 through switching arrangement such as relay 205, switch 206 and the second input terminal 204 of starter motor 202 is connected to the negative terminal of battery 201 without any grounding requirement as because of above described arrangements (Figure 1) in the starter motor 202, current drawn by said starter motor 202 is considerably low.

Further, the manner of assembling the embodiments described are not necessarily to be performed only in the sequence illustrated or each step only at the time indicated.

Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

WHAT IS CLAIMED IS:

1. An electric starter motor characterized by its no grounding requirement, compact size and ability to produce high torque force comprising, in combination;

a main housing member defining a front housing member, a centre housing member and a rear housing member;

an armature assembly extending through the centre housing member and defining a front armature member comprising a pinion shaft module and a rear armature 'member comprising a commutator, such that a rotatable armature shaft is assembled with the front armature member through engagement of said pinion shaft module and a reduction gear housed in the front housing member; and

a brush card, of dielectric material housed in the rear housing member such that a plurality of electrical conducting brushes engaged with rear armature assembly through the commutator, is mounted on said brush card.

2. The electric starter motor, as claimed in claim 1, wherein the front and rear housing member is made up of resin material in order to facilitate compact size of the electric starter.

3. The electric starter motor, as claimed in claim 1, wherein the front housing member is made up of metal.

4. The electric starter motor, as claimed in claim 1, wherein the centre housing member is made up of metal.

5. The electric starter motor, as claimed in claim 1, wherein the plurality of electrical conducting brushes is engaging the armature to engine starter drive means operatively connected to said armature.

6. The electric starter motor, as claimed in claim 4, wherein the plurality of electrical conducting brushes is made up of metal graphite.

7. The electric starter motor, as claimed in claim 1, is characterized by its compact size and low power input resulting in no grounding requirement.